Here is a summary of some of the previous research activities within the TOMCAT team. Click on an item to be directed to a more detailed project description.
Dynamic in-vivo lung imaging at the micrometer scale
Apart from that, our interests also extend to the study of other lung diseases such as emphysema and fibrosis. Our results will have direct implications on the current knowledge and understanding when dealing with lung diseases in clinics. For instance, a fundamental understanding of VILI would be crucial for developing better ventilation strategies for patients.
X-ray phase contrast tomographic imaging and analysis of the lung at the micrometer scale
Reconstruction of the mouse brain vascular networks with high-resolution synchrotron radiation X-ray tomographic microscopy
X-ray grating interferometry for phase-contrast imaging at the Swiss Light Source
Impact of phase-contrast X-ray imaging in cochlear micro-anatomy investigation
Virtual Reading of a Large Ancient Handwritten Science Book
Full-Field Transmission X-ray Microscopy using a Photon Counting Pixel Detector
Lossy Compression for CT Datasets
The core idea of lossy compression is to subtly modify an image such that it can be compressed well while keeping the visual appearance as much as possible. For average compression ratios, this will typically lead to tiny ‘ghost’ structures around more prominent image features or smoothing that the human eye will miss. In the case at hand, however, where the images serve as input to the first stage of a longer processing pipeline, such modifications may lead to artefacts in the final tomographic reconstructions. This project aims at evaluating different lossy compression schemes and at investigating the impact of their respective artefacts onto reconstruction quality.
Laboratory imaging research
Dual Phase Grating Interferometer
Omnidirectional Dark-Field Imaging with Circular Unit Cell Gratings
Single Shot Differential Phase Contrast Imaging with Single Photon Sensitive Detectors
Differential phase contrast for X-ray tubes above 100 kVp
Ex-vivo study of suspicious microcalcifications in breast tissue biopsies
Feasibility study of an X-ray phase contrast breast CT scanner
Micro and Nano Fabrication
Fabrication of gratings for phase contrast X-ray imaging
Grating interferometry is proved to be one of the most promising techniques for phase contrast X-ray imaging. Typical grating interferometer consists of a phase shifting grating (G1), analyzing grating (G2) and an optional absorbing source grating (G0). Usually, required grating period is in a range of few microns. The height of the lines of G1 grating should provide a certain phase shift, while the height of the grating lines of G2 should be sufficient to suppress radiation of defined energy. In both cases, structures with heights of tens (or even hundreds) of micrometers are required. However, the realization of structures with so high aspect ratios yet having sufficient quality over the large area is demanding. We develop fabrication procedures which enable such gratings. We produce G1 gratings in Si by reactive ion etching using Bosch technique  or by metal assisted chemical etching . The absorbing G0 and G2 gratings are produced by filling Si templates with metal utilizing electroplating, metal casting  or atomic layer deposition . Larger structures can alternatively be produced by laser cutting in W foils.